Fix mouse wheel scrolling on PDFs.

third_party/WebKit/Source/web/WebSettingsImpl.h

Index: third_party/WebKit/Source/web/WebSettingsImpl.h
diff --git a/third_party/WebKit/Source/web/WebSettingsImpl.h b/third_party/WebKit/Source/web/WebSettingsImpl.h
index 216c41504cb3fab5986f055921245a6fe121c023..7babca75c844e36f2ccea45d36f490c7a8639ee9 100644
--- a/third_party/WebKit/Source/web/WebSettingsImpl.h
+++ b/third_party/WebKit/Source/web/WebSettingsImpl.h
@@ -191,6 +191,7 @@ public:
     void setViewportMetaZeroValuesQuirk(bool) override;
     void setWebGLErrorsToConsoleEnabled(bool) override;
     void setWebSecurityEnabled(bool) override;
+    void setWheelGesturesEnabled(bool) override;
     void setWideViewportQuirkEnabled(bool) override;
     void setXSSAuditorEnabled(bool) override;
 
@@ -208,6 +209,7 @@ public:
 
     void setMockGestureTapHighlightsEnabled(bool);
     bool mockGestureTapHighlightsEnabled() const;
+    bool wheelGesturesEnabled() const;
 
 private:
     Settings* m_settings;